MUNICH, Germany — Munich tapped the keg Saturday on the world’s biggest beer festival, Oktoberfest, with six million revelers expected just as the German city is grappling with a record refugee influx.

The celebration of traditional Bavarian culture with its oompah music and beloved frothy beverage kicked off when Mayor Dieter Reiter cracked the first beer barrel with two mallet blows and offered a toast to a “peaceful” Oktoberfest.

While the mood in town in the run-up to the 16-day event remained undauntedly festive, Munich had to plan its huge annual party just as it became a flashpoint of Europe’s migrant crisis.

More than 20,000 people, many of them Syrians, Afghans and Iraqis fleeing war, poverty and persecution, have descended on the city of 1.4 million on each of the last two weekends.

They met with an overwhelmingly positive reception from the public, including an outpouring of donations.

But the number of arrivals dropped markedly in the last week to a few hundred per day due to border controls implemented from Sunday at the request of Bavarian’s conservative authorities, who had described themselves as overwhelmed by developments.